Braking mechanism



March 29, 1938, NELL 2112,609

BRAK I NG MECHAN I S M Fild Feb. 3, 19:54 3 Sheets-Sheet 1 FIG.3.

Inventar Z Att y March 29, 1938.

S. SCHNELL BRAKING MECHANISM 3 Sheets-Sheetf Filed Feb. 5, 1934 Inventor gz;; AM

Atty

March 29, 1938. SCHNELL 2,112,609

BRAKING MECHANISM Filed Feb. 3, 1934 5 Sheets-Sheet 3 Atty Patented Mar. 29, 1938 k k TIVUNITED STATES PATENT OFFICE ner Ele(:tric Corporation, St; Louis, Mo. a eo!- poration of Delaware Applicat ion Februgry 3, 1934, Seriil Nq. 7092553 -12 =Clalms. (01. 18 8-152) Q My invention. r el.tes to b rakihg mechanism Support und compr ises a dylinder 2, a. piSton 3,

' and niore pa zticularly .t omeails for taking up und al reservoirl; The reservoir l Is in com muslack in braking Systems 9Ln'd t mens for changnicatiqn with thecylinder by means of compen- Ing the pedal leverag rati. v sating port when the piston is movd to 1ts 17e In both hydrauli calljz and rheqjhaniqallya ctutracted position again shthe stop 6 by the plston 5 ated brakes a.s now manufactred, itisneoessary return spring, as shown in Figurel. vThe. piston to 'move;the brake pedal a considerable distande is provided with the usual paqking cup I und a beIforethe brake shoes are brought int0 'cq'ntact secondary packing 8. The c ylinder ab the reza.rwith the brgk e This p4ad2zlmoyeme nt o1 the pistonhead is at all times in communlcawhich perfprn'1s nqusef ul work and is therefo re, tion with the reservoir by means of the opening 10 a waste of physica)l effort, also necessitat es, using 9. The pipe I0 provides communication between a sma.ller pedal leverage ratio sing; the pegdal the cylinder a.nd each of the bxake shoe' actuattra.vel effeqtivq 1x1 abplying bra kir ;g firessure Is Ing motors (not shown). In prior standardc011- reduggd k structlons the piston is actu ated by the 'brake.

One of the objects of my inveptlbn is tqp rovide pedal throughconnecting means pivoted thereto. 15 a b raking system with means for taking up slack In the construction abovedescribed, when the in abrakin'g systemwithout movement of the pedal is moved to actuate thepiston 1:0 apply brake pedal. y pnessure to the system, the pedal must; be ini- Anoth er object of my invention ls to Provide vially moved a considerable distance be f0re any power-operated means for taking -up slack in a. braking efiect is secur ed sinceihe-piston 3 has 20 brake systemwhich means functions when the to be flrst moved past the port ito close the operators foot i5 placed.upon the peda.l pad and cylinder and then moved an additional distance be1ore the pedal is moved. to bulld up sufficient pressure to move the brake Still another object of my invention 1s to proshoes into engagementwith their drums. 'I'his vide means whereby either o f severalpedal lever Initial pedal movement necessary totake up slack 35 age ratios may be employed to operate a brake in the braking system and to secure a braking withouia change in the total pedal travel neceseffect, may be as great as two or three Inches sary for agiven displacernent cf the brake actuat the pedal pad, and 1t often exceeds the amount ating elemen t. 1 v of pedal movementnecessary to produce the-de- 3o, Other objects of my invention will become apsired braking a.ctionafber -the slack has been parent f ro m the following description taken in taken up. Thispedal movement to take up the connection with the accompanying drawings slack in I;he braking systemdecreases thepedal showing several embodiments thereof in which traveleflective in applyingbraking pressureand Figupe 1.15 a view, partly in crpss-section, of a prevents the use of a. greacer pedal leverage ratio.

hydraulic compressor and pedal themf or em- Therefore, the elimination ofzthis movement Is 35 bodyihgmy invention; Figure 2 is a cross-sechighly desirable. tional i iew on the l ine 2-2 of Figure 1;.Flgure In .accordance-with myiinvention I have de- 3 is a cross-sectional view of the valve mechanism vised means whereby the s1ac k 1 in 'the braking for the Esuction motor Figur3 4 i s an enlarged system will automaticallybe taken up -as soon as cross-selqtional view;of the control port fpr the the operator's foot is placed on the; pad of the 40 va lve; FIgures .5 and 6 are views similar t0 tha.t peda.l and without the necessity of any movement of 11gur e;lshowing differe nt operating posiof the peda1. Also, bymes,nsof myinventionl tions; Figure 7 is a.wiew illustrating a modificaam able to employ either of two pedal leverage tion of the structure shown by Figure l; Figures ratios to operate the brakes without a. change in 8 and 9 are crosssectional views taken on the the peda1 travel necessary to movethe compres- 45 Iines 8- 8 and 9--9 respectively, of Figure 7 sor piston a selected distaxice. Figure 10 Is a yiew illustrating a furthermodifi- ..The brake pedal II a.t its pivoted end is bifurcation;/Figure 11 is. a cross sectional view taken cabed to form a .s1ot I3 (Figure2), thelegs I3 on the 1ine II -I I- pf jEiguz y6 1 0; fand Figme 12 being provlded with a bearing boss I5 for receivisa v;w shoWir ig how the invehj sion isembodied Ing the pivot pin I6. The .usual coiled spring I'I 50 in mechanicllY-actuatgdbraking mechanism. maintains the peda1 in its retracted. posltion R eferring to Figures 1 to 6, inclusive, the nuagainstthe floor boards of.the vehiele Ea.ch leg me ral I indicatesa standard type of compensat- I4 is formed with coinciding inclined s 10ts18 fing compressor used on a hydraulic brake systhrough which extends a pin I9 for connecting tem, th1s compressor is mount;ed on. a auita hle tl 1 e Pedal to, the forked end of the piston rod I2. 55

inches from the pedal plvot-and I;he pin as belng 3 inches from the pedal pivot. If the pin I9 is in the lower end of the slotwhen the pedal Is moved (the suction motor hdvlng been operat- 5 ed), und If we consider the'slo'c I8 as being approxlmately one-halfinch logg, the ratio w1ll'be 6 to 1 'for then the pin I9 will only be 2 inches fron'1 the pivot 'of the pedal. Regardless cf the leverage ratio being usecl, "the final posltion -o1 the compressor piston for affull pedal travel will be the same, due to the fact that the slot I8 1s.

vertlcal at the end of .the Pedal travel.

In Figures 7, 8 and 9'I have shown my Inventlon embodied In a. slightly modlfled construction. The pin und slot connection between the plston 1"0d and the pedal is replaczed bya toggle cdnnection. 'I'he lower end of thebedal I I 1's provlded with an off-set forked end 42 which receives thepedal pivot pin I 6 The forked end of the piston rod I2 i's ri lvotzatlly con nected by a pa.ir of links 43 with the' pedal H. 'I'he suction motor 20 and I;he control v'alve 21 are suspended onthe pivot pin IG in the same manner as vin Figure 1. The connecting link 25 actuated by the suctior'1 motor 20, is connect iad to the pivoted connection between 'the piston rodl1fland the links 43. The remainlng lsti= ur;t ure is thesame as that shown in Flgure' 1.Th peration of I;his modiflcatin is the sameaS that of .Figure 1.

ondary pedal pad, the suctlon motor Is immedlately operated am] the movement of the link 25' stralghtens out the toggle conn ection be-f tween the piston rod I2 and the pedal, thus mov- Ing the compressor piston forward, taking up slack in the brakes, und changing the leverage ratio of I:he pedal.

In Figures 10 und 11 I have shown the links 43 of Flgure 7 replaced by a pair of bell-crank levers pivoted to the peda.l II. The ends 45' of the bell-crank levers extend .to a. point adjacent the pedal pivot I5 and are connected by means of a flexible oable 48 to the suction motor 20 mounted (m a fixed part of the vehicle. When the suction motor is operated, the bellcrank levers are rotated on the pedal, thereby stralightening I:he boggle connection between the' piston rod I2 and the pedal, thus moving the compressor piston and taking up slack in the brakes. v

In Flgure 12 I have shown how my invention may be applier i to mechanically actuated brakes wherein the pedal operates a cross-shaft 41 'which in turn operates the brakes bysultable rodding of well known construction. 'I'he slack take-up structure illustrated is the same as that shown in Figure 1 except that I:he nisten rod I2 is replaced by a pull-rod 48 connected I:o arm 49 on the closs-shaft 41. When the suctlon motor is operated the pin I9 1s moved in the slots I8, thus moving the rod I2 longitudinally to I;ake up slack in the braking system.

It is to be noted that a braking system equipped with my slack take-up und pedal leverage ratio changing device will always operate in the usual manner in case the device should become disabled.

Being avfirare of the possibility of many other' modifications In the particular structures'herein Havlng fully described my invention, what I Whenthe operators foot is pla.cd im the secthe pedal whereby the rod 1s movable wlththe pedal, said connectlng means perniittlng sa.idv

rod to be moved longltucllnally indiapendently of the pedal, means comprlsing a fluid motorrnovable wiIsh the' pedal for moving seid rod; -Independently of the pedal to take up sla.ck in the brakingmechanism and a valve on the pedal pad for governingthe fluid motor.

2. In braking mechanism, a. pivoted br'ake pedal provided with a. slot incllned withrespect to a vertical axis when the pedal is in an inoperative position, a longitudinally mov&ble rpd for operating the brakeand proVided with a pin extending into saidslot, a. fluld'n'1otr pivotally mounted on the pivot of sa.id p'edalconnecting means between the motor sind the pin forv moving thepin in I:he slot, a control valv'e.

for said motor, and means onsaid brake pzdaIl for governing said control valve-with'ot mdvement of the pedal.

3. Inhydraulic brake actuating mechan'ism,'a cylinder, a. piston movable therein, a. reseryoir in commum'cation w1th the cylinderwhdan the piston ls in retracted posltlona plvoted lever, a rod connected to the lever and the plston whe'reby the plston may be actuated by movement o! the lever about its pivot, and means opera ble wlthdut movement of the lever for changlng I; he leverage ratio 01 the lever und 1'or simultaneously moving the rod longitudinally to thereby move the piston In pressure applying direction and cut 011 communication between the reservoir and the -cyl- Inder. V

4. In hydraulic brake actuating mechanism. a cylinder, a piston movable therein, a reservoir in cor'nmunication wlth-the cyllnder when the piston ls in retracted positlon. a pivoted lever, a

-rod connected to the lever and the plston whereby the piston may be actuated by movement of the lever about. its p1vot, means 'operable without movenient of the lever for moving the connectlon between the lever und I:he rod closer to the lever plvqt and means 1'or moving the rod loxagitudlnally when sald connection is moved I;o therebjr move the plston In pressure applying dlrectlon and cut ofl' communication between the reservoir and the cylinder.

5. In braking mechanlsm, a. movable element for operatlng the brakes, an actuating member for said element, connecting meana for continuously maintaining an ope'rative connectlon between the actuating member and the element buI; permittlng movement of the elemez1t relative to -said member without breaklng said operative connection whereby any movement of the actuating member will cause a. simultaneous movement cf the element, and fluid pressure-operated means for moving said element in brake applying direction without movement of v the actuatlng member, said last named means embodying a control valve 011 the actuating member.

6. In braking mechanlsm, an elemeni: Ior operating the brakes, a lever, a connection between the lever and the element whereby the elem(mt may at all tlmes be moved with each movement o! the lever but permitting said element to be moved relatively to the lever, means tot moving sa.ld element indepe'ndently of any movement of the lever to take up slack in the braking mechanism,

fluid pressure means for operatlng said flrst 

